A nonvolatile semiconductor storage device such as ReRAM (Resistance Random Access Memory) is becoming popular for its capacity to store large amount of data and for its ease in three dimensionalization. The data storing portion of ReRAM, which may be a stacked structure disposed between a word line and a bit line, may comprise metal such as tungsten. When processing the stacked structure including metal by dry etching, for example, the metal may be ejected by the sputtering effect of ions and develop deposits including metal at the bottom portions of patterns. This may lead to shorting of adjacent patterns.